/**
* Acquires a repository lock and begins a matching MDR transaction (shared lock for read, or
* exclusive lock for write). Typical usage is start of SQL statement preparation (e.g.
* readOnly=true for DML or query, false for DDL).
*
* @param readOnly if true, a shared lock is acquired on the catalog; otherwise, an exclusive lock
* is acquired
*/
public void beginLockedTxn(boolean readOnly) {
int level = (readOnly) ? 1 : 2;
// TODO jvs 24-Jan-2007: Get rid of downcast here and below by
// making all creation of FarragoReposTxnContext go through
// factory method interface on FarragoRepos.
((FarragoReposImpl) repos).lockRepos(level);
// Don't set lockLevel until we've successfully acquired the lock
lockLevel = level;
if (readOnly) {
beginReadTxn();
} else {
beginWriteTxn();
}
}
/** Ends exclusive access mode for the repository. */
public void endExclusiveAccess() {
((FarragoReposImpl) repos).endExclusiveAccess();
}
/**
* Puts the repository in exclusive access mode. When in this mode, subsequent attempts to lock
* the repository will return an exception immediately rather than wait for a required repository
* lock to become available.
*/
public void beginExclusiveAccess() {
((FarragoReposImpl) repos).beginExclusiveAccess();
}
/**
* Releases lock acquired by beginLockedTxn. Caller should already have ended transaction with
* either commit or rollback.
*/
public void unlockAfterTxn() {
if (lockLevel != 0) {
((FarragoReposImpl) repos).unlockRepos(lockLevel);
lockLevel = 0;
}
}